Dr. Julie, a.k.a. Scientific Chick, brings you insights into what's happening in the world of life sciences. Straight from the scientific source, relevant information you should know about, in plain language.

Saturday, July 21, 2012

In our early years, we are taught about the five senses:
hearing, sight, taste, touch and smell. These senses (supposedly) make up our
own personal toolbox for perceiving the world around us, and we are initially
taught that our senses give us an accurate representation of what we perceive:
cookies always smell like cookies, cheezy poofs always taste oh-so-good.

This idea that our brain perceives the world exactly as it
is starts to break down when we are exposed to optical illusions: images that
differ from what we think is real. One of my favorite ones is on the right: the
A square and the B square are actually the same shade of grey, even though we
perceive them to be different. As it turns out, neuroscientists are
increasingly finding out that most of our senses, not just vision, are far from
perfect when it comes to representing the world accurately. How we feel, what
we are doing, what we just did, pretty much anything can influence our
perception.

In a recent study about perception, researchers investigated
the relationship between morality and taste. They started by having
participants read a short story. Not everybody got the same story to read: a
third of the participants read a story in which something morally bad happens
(shoplifting, or a politician accepting a bribe), a third read a story in which
something morally good happens (a gift to a homeless family, or a good
Samaritan stopping a mugging), and a third read a story in which something
boring happens (a student choosing a major, or waiters chit chatting). The
participants were then asked to rate the morality of the story, and not
surprisingly, they rated the stories exactly as you would expect – the
shoplifting and bribe-accepting as being morally bad, and so on.

The researchers then pretended that the study was over, and
that they were now starting a new study that had to do with product-testing.
The participants were asked to drink a teaspoon of a mysterious drink (in
reality, diluted blue Gatorade), and then rate the taste of the drink on a
scale from very disgusting to very delicious. Can you see where this is going?

As you might have guessed, the participants that had read a
“morally bad” story rated the drink as more disgusting, and the participants
that had read a “morally good” story rated it as more delicious (the ones who
got the boring story rated it somewhere in the middle). That is to say, the
participant’s experience of a moral judgment significantly influenced their
perception of taste. Seems like we can’t trust any of our senses!

The researchers discussed the results of this study in the
context of how we process morality and so on, but I think it’s even more
interesting to think of this as a prime example of just how much our brain puts
a personal slant on everything we experience. I also see implications for
issues like overeating and emotional eating.

Can you think of a time when food tasted different because
of emotional reasons? Share in the comments!

Monday, July 16, 2012

I think it’s pretty safe for me to assume that you’re
sitting down right now. Some of you might be so lucky to have a treadmill desk
(on my long list of wants) or you might be reading this on your mobile device
while waiting in line at the grocery store, but chances are most of you are
sitting. Many people around the world do what I call “sitting for a living”,
meaning working at a desk for the larger portion of the day. A recent study
reported that Taiwan, Norway, Saudi Arabia and Japan are the “most seated”
countries with people sitting over 6 hours per day. It’s a no-brainer that
sitting all day is bad for your health – it’s been associated with health
issues like Type 2 diabetes and cardiovascular disease. Conversely, it’s also
known that exercise is good for you and helps prevent health issues like – you
guessed it – Type 2 diabetes and cardiovascular disease. Based on these
findings, the government has established guidelines suggesting adults get at
least 150 minutes of moderate to vigorous exercise per week to benefit from
physical activity.

Long work hours combined with all this evidence about the
health benefits of exercise has led to a new label: what I call the “active
couch potato”, one who is both sedentary and physically active. These people,
like me, work 8- to 10-hour days at a desk, but also exercise – for example,
they cycle to work, or jog regularly. So the question becomes: is regular
exercise sufficient to offset sitting all day on most days?

A recent study tries to shed light on the relationship
between sitting and life expectancy, regardless of exercise. After seeing a
number of dubious headlines about this study such as “Sitting less can boost
your life expectancy” and “Sitting ourselves to death” (gasp!), I thought I’d
take a look at the original research and report back.

The researchers carried out a “meta-analysis”, which
essentially means an “analysis of analyses”. They looked through previously
published scientific articles on the topics of sitting and life expectancy,
pooled the results together, and crunched the numbers to get a “big picture”.
To make their results easier to understand, they divided sitting habits in
three levels: level 1 means sitting less than a quarter of the time in a normal
day, level 2 means sitting about half the time, and level three means sitting
three quarters of the time or more. What their results show is that going from
level 2 or 3 to level 1 (meaning sitting less) can mean a gain of 2 years in
life expectancy.

So what? Do we really conclude that sitting is a silent
killer?

Not so fast. We have many reasons to believe that sitting is
bad for our health, but this article isn’t necessarily one of them. For one
thing, the researchers themselves point out that their results don’t mean that
someone who sits less can expect to live longer. Life expectancy is a measure
that can only apply to populations, not to individuals, so while the study is
relevant in a “big picture” kind of way, it means little for your own personal
habits and life expectancy.

The authors also make one big assumption in their model:
that sitting more causes a shortened
life expectancy. However, the study results don’t tell us whether there is a
direct cause-and-effect relationship. I talked about confounders in previous posts, and this is a perfect place to continue this discussion.
For my new readers, confounders are variables that the researcher didn’t take
into consideration, which could explain his results in a different way. For
example, in this instance, the researchers find that sitting more shortens life
expectancy. However, the real explanation could be that people who sit more end
up eating more spicy Cheetos, and it’s the chemicals in the spicy Cheetos that
actually shortens their life expectancy. See what I mean? Of course this is a
silly example, but you get the idea (and of course I will never give up spicy
Cheetos).

Can you think of possible (silly or not!) confounders in
this study? Share in the comments!

You can count on more articles about sitting in the future.
Since this one didn’t really answer whether sitting and exercising cancel out,
I’ll keep looking.

Reference: Sedentary behaviour and life expectancy in the USA: a cause-deleted life table analysis. (2012) Katzmaryk PT, Lee I-M. BMJ Open 2:e000828.

Sunday, July 8, 2012

There has been a lot of discussion in the news recently about the discovery of the Higgs boson particle at the Large Hadron Collider in Geneva.

I'm sure some of you would like to know more about this, and I would have loved to write a good post about the discovery and its implications. Sadly, my knowledge of subatomic particle physics is somewhat limited (and by limited I mean nonexistent).

So instead, I recommend the following video for an introduction to the Higgs boson:

Friday, July 6, 2012

We’re all growing old – for all the recent advances in
science and all the predictions of science fiction, this is still an
inescapable fact. By 2050, there will be roughly 89 million older adults in the
US, twice as many as there are now. While old age chases most of us down if
we’re lucky, that doesn’t mean we’re entirely powerless in the process.

Previous entries in my blog looked at various ways to
promote healthy aging: walking and lifting weights, eating less, learning languages. Some of these lifestyle changes, like exercise, are easy to
incorporate later in life, while others, like bilingualism, may depend on the
environment you grew up in. Today’s new finding about healthy aging fits in the
latter category. It's a bit like a lottery: were you one of the lucky ones who benefited from an anti-aging activity in your youth?

Researchers were interested in how the brain responds to
sound. We already know that brain structures that lie at the base of your
brain, called subcortical structures (sub > beneath, cortical > the outer
layer of your brain) are important for detecting fast-changing sounds like the
ones we make when we talk. The precise timing of your brain reacting to sounds
degrades as you get older, and scientists believe this is why grandma sometimes
doesn’t really follow what you’re saying.

In this study, the researchers measured the precision of
this timing by putting electrodes on participants’ heads (the outside only!) and
recording the signals their brains generated when they heard the syllable “da”.
As expected, the older participants didn’t have as precise a timing as younger
ones. More interestingly, however, was that this age-related decline wasn’t
nearly as bad in participants who were musicians.

So the take-home message is that lifelong musical experience
can help make your brain better equipped to deal with aging. No doubt it also comes with other benefits - my grandma, in her eighties, had forgotten much of her adult years but still delighted fellow residents of her care home with her flawless rendition of the "Sweet bye and bye". Now of course
while this is an interesting article, the results don't come as a huge surprise – by now you probably have figured out that the
whole “use if or lose it” saying has a lot of truth to it.

Conveniently, I just bought a piano. Now if only I could
reap all the benefits just by looking at it…

About Me

Dr. Julie is an Assistant Professor of Neurology at the National Core for Neuroethics and the Djavad Mowafaghian Centre for Brain Health at the University of British Columbia. She holds a PhD in Neuroscience.